X-linked carriers of chronic granulomatous disease: Illness, lyonization, and stability

Considerations in the Diagnosis of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency that is caused by defects in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. The disease presents in most patients initially with infection, especially of the lymph nodes, lung, liver, bone, and skin. Patients with CGD are susceptible to a narrow spectrum of pathogens, and Staphylococcus aureus, Burkholderia cepacia complex, Serratia marcescens, Nocardia species, and Aspergillus species are the most common organisms implicated in North America. Granuloma formation, most frequently in the gastrointestinal and genitourinary systems, is a common complication of CGD and can be seen even before diagnosis. An increased incidence of autoimmune disease has also been described in patients with CGD and X-linked female carriers. In patients who present with signs and symptoms consistent with CGD, a flow cytometric dihydrorhodamine neutrophil respiratory burst assay is a quick and cost-effective way to evaluate NADPH oxidase function. The purpose of this review is to highlight considerations for and challenges in the diagnosis of CGD.

Future of Care for Patients With Chronic Granulomatous Disease: Gene Therapy and Targeted Molecular Medicine

Chronic granulomatous disease is a rare and potentially fatal disorder of neutrophil function. Beyond current medical management and hematopoietic stem cell transplantation, new methods of gene therapy that use lentiviral vectors or gene editing might extend curative therapies to patients who lack a suitable transplantation donor while eliminating the risk of graft-versus-host disease. Furthermore, new therapies focused on altering the biology of phagolysosomes might offer novel targeted treatments for inflammatory complications in patients with chronic granulomatous disease.

Chronic Granulomatous Disease: Epidemiology, Pathophysiology, and Genetic Basis of Disease

Chronic Granulomatous Disease is one of the classic primary immunodeficiencies of childhood. While the incidence and severity of bacterial and fungal infections have been greatly reduced in this patient population, much remains to be learned about the pathophysiology of the disease, particularly for autoinflammatory manifestations. In this review, we examine the epidemiology, pathophysiology, and genetic basis for CGD.

Allogeneic Hematopoietic Cell Transplantation for Chronic Granulomatous Disease: Controversies and State of the Art

Chronic granulomatous disease (CGD) is a congenital disorder characterized by recurrent life-threatening bacterial and fungal infections and development of severe inflammation secondary to a congenital defect in 1 of the 5 phagocyte oxidase (phox) subunits of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. Hematopoietic cell transplant (HCT) is a curative treatment for patients with CGD that provides donor neutrophils with functional NADPH and superoxide anion production. Many characteristics of CGD, including preexisting infection and inflammation and the potential for cure with mixed-donor chimerism, influence the transplant approach and patient outcome. Because of the dangers of short-term death, graft-versus-host disease, and late effects from chemotherapy, HCT historically has been reserved for patients with high-risk disease and a matched donor. However, as advances in CGD and HCT treatments have evolved, recommendations on transplant eligibility also must be amended, but the development of modern guidelines has proven difficult. In this review, we provide an overview of HCT in patients with CGD, including the debate over HCT indications in them, the unique aspects of CGD that can complicate HCT, and a summary of transplant outcomes.

Noninfectious Manifestations and Complications of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD), a primary immunodeficiency characterized by a deficient neutrophil oxidative burst and the inadequate killing of microbes, is well known to cause a significantly increased risk of invasive infection. However, infectious complications are not the sole manifestations of CGD; substantial additional morbidity is driven by noninfectious complications also. These complications can include, for example, a wide range of inflammatory diseases that affect the gastrointestinal tract, lung, skin, and genitourinary tract and overt autoimmune disease. These diseases can occur at any age and are especially problematic in adolescents and adults with CGD. Many of these noninfectious complications present a highly challenging therapeutic conundrum, wherein immunosuppression must be balanced against an already markedly increased risk of invasive fungal and bacterial infections. In this review, the myriad noninfectious complications of CGD are discussed, as are important gaps in our understanding of these processes, which warrant further investigation.

Clinical considerations in the hematopoietic stem cell transplant management of primary immunodeficiencies

INTRODUCTION

Primary immunodeficiencies (PID) are genetic immune disorders causing increased predisposition to infections and autoimmunity. The only curative procedure is hematopoietic stem cell transplantation (HSCT), results from which have improved dramatically since 2000. Complications remain a serious issue, especially in HLA non-identical transplantation. In PID patients, persistent infection and autoimmunity with end-organ damage cause particular problems with approach to transplantation. This article examines these, emphasising approach to management and consequences. Areas covered: It is challenging to know which patients should be offered HSCT. As new diseases are discovered, data are required to determine natural history, and HSCT outcomes. Treatment of adults can be challenging, although HSCT outcomes are encouraging. New methods of T-lymphocyte depletion show results comparable to those of matched sibling donor transplants. New cellular therapies to treat viral infections show promising results, and immunomodulatory methods are successful in treating acute graft-versus-host disease. Expert commentary: New T-lymphocyte depletion methods are a paradigm shift in approach to HSCT for PID. In combination with new cellular approaches to treating viral infection, immunomodulatory approaches to acute graft-versus-host disease and better understanding of endothelial activation syndromes, survival approaches 90%. Widespread introduction of newborn screening for severe combined immunodeficiencies will improve survival further.

High Incidence of Autoimmune Disease after Hematopoietic Stem Cell Transplantation for Chronic Granulomatous Disease

There is a lack of consensus regarding the role and method of hematopoietic stem cell transplantation (HSCT) on patients with chronic granulomatous disease (CGD). Long-term follow-up after HSCT in these patient population is essential to know its potential complications and decide who will benefit the most from HSCT. We report the outcome of HSCT and long-term follow-up in 24 patients with CGD, transplanted in our center from either related (n = 6) or unrelated (n = 18) donors, over a 12-year period (2003 to 2015), using high-dose alemtuzumab in the preparative regimen. We evaluated the incidence and timing of adverse events and potential risk factors. We described in detailed the novel finding of increased autoimmunity after HSCT in patients with CGD. At a median follow-up of 1460 days, 22 patients were full donor chimeras, and 2 patients had stable mixed chimerism. All assessable patients showed normalization of their neutrophil oxidative burst test. None of the patients developed grades II to IV acute graft-versus-host disease, and no patient had chronic graft-versus-host disease. Twelve of 24 patients developed 17 autoimmune diseases (ADs). Severe ADs (cytopenia and neuropathy) occurred exclusively in the unrelated donor setting and mainly in the first year after HSCT, whereas thyroid AD occurred in the related donor setting as well and more than 3 years after HSCT. Two patients died due to infectious complications after developing autoimmune cytopenias. One additional patient suffered severe brain injury. The remaining 21 patients have long-term Lansky scores ≥ 80. The outcome of HSCT from unrelated donors is comparable with related donors but might carry an increased risk of developing severe AD. A lower dose of alemtuzumab may reduce this risk and should be tested in further studies.

Hematopoietic cell transplantation in primary immunodeficiency - conventional and emerging indications

INTRODUCTION

Hematopoietic stem cell transplantation (HSCT) is an established curative treatment for many primary immunodeficiencies. Advances in donor selection, graft manipulation, conditioning and treatment of complications, mean that survival for many conditions is now around 90%. Next generation sequencing is identifying new immunodeficiencies, many of which are treatable with HSCT. Challenges remain however with short and long-term sequalae. This article reviews latest developments in HSCT for conventional primary immunodeficiencies and presents data on outcome for emerging diseases, Areas covered: This article reviews recently published literature detailing advances, particularly in conditioning regimens and new methods of T-lymphocyte depletion, as well as new information regarding approach and out come of transplanting patients with conventional primary immunodeficiencies. The article reviews data regarding transplant outcomes for newly described primary immunodeficiencies, particularly those associated with gain-of-function mutations. Expert commentary: New methods of graft manipulation have had significant impact on HSCT outcomes, with the range of PIDs treated using T-lymphocyte depletion significantly expanded. Outcomes for newly described diseases with variable phenotypes and clinical features, transplanted when the diagnosis was unknown are beginning to be described, and will improve as patients are identified earlier, and targeted therapies such as JAK inhibitors are used as a bridge to transplantation.

NADPH Oxidase Deficiency: A Multisystem Approach

The immune system is a complex system able to recognize a wide variety of host agents, through different biological processes. For example, controlled changes in the redox state are able to start different pathways in immune cells and are involved in the killing of microbes. The generation and release of ROS in the form of an “oxidative burst” represent the pivotal mechanism by which phagocytic cells are able to destroy pathogens. On the other hand, impaired oxidative balance is also implicated in the pathogenesis of inflammatory complications, which may affect the function of many body systems. NADPH oxidase (NOX) plays a pivotal role in the production of ROS, and the defect of its different subunits leads to the development of chronic granulomatous disease (CGD). The defect of the different NOX subunits in CGD affects different organs. In this context, this review will be focused on the description of the effect of NOX2 deficiency in different body systems. Moreover, we will also focus our attention on the novel insight in the pathogenesis of immunodeficiency and inflammation-related manifestations and on the protective role of NOX2 deficiency against the development of atherosclerosis.

A Review of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defects in any of the five subunits of the NADPH oxidase complex responsible for the respiratory burst in phagocytic leukocytes. Patients with CGD are at increased risk of life-threatening infections with catalase-positive bacteria and fungi and inflammatory complications such as CGD colitis. The implementation of routine antimicrobial prophylaxis and the advent of azole antifungals has considerably improved overall survival. Nevertheless, life expectancy remains decreased compared to the general population. Inflammatory complications are a significant contributor to morbidity in CGD, and they are often refractory to standard therapies. At present, hematopoietic stem cell transplantation (HCT) is the only curative treatment, and transplantation outcomes have improved over the last few decades with overall survival rates now > 90% in children less than 14 years of age. However, there remains debate as to the optimal conditioning regimen, and there is question as to how to manage adolescent and adult patients. The current evidence suggests that myeloablative conditioning results is more durable myeloid engraftment but with increased toxicity and high rates of graft-versus-host disease. In recent years, gene therapy has been proposed as an alternative to HCT for patients without an HLA-matched donor. However, results to date have not been encouraging. with negligible long-term engraftment of gene-corrected hematopoietic stem cells and reports of myelodysplastic syndrome due to insertional mutagenesis. Multicenter trials are currently underway in the United States and Europe using a SIN-lentiviral vector under the control of a myeloid-specific promoter, and, should the trials be successful, gene therapy may be a viable option for patients with CGD in the future.

Recent advances in understanding and treating chronic granulomatous disease

A number of recent advances have been made in the epidemiology and treatment of chronic granulomatous disease. Several reports from developing regions describe the presentations and progress of local populations, highlighting complications due to Bacillus Calmette-Guérin vaccination. A number of new reports describe complications of chronic granulomatous disease in adult patients, as more survivors reach adulthood. The complications experienced by X-linked carriers are particularly highlighted in three new reports, confirming that infection and inflammatory or autoimmune conditions are more common and severe than previously recognised. Finally, definitive treatment with haematopoietic stem cell transplantation and gene therapy is reviewed.